1. Field of the Invention
The present invention relates to optical communication devices, and more particularly to a test probe which permit fast and efficient testings of optical devices, preferably when mounted upon silicon optical benches.
2. Description of the Related Art
In the optical data communications industry, optical component subassemblies for the optical link transmitter and receiver modules employ a multi-component carrier made from silicon. This carrier is called a Silicon Optical Bench (SiOB). The SiOB has etched features in the silicon for aligning optical passive components, and high speed electrical traces on the silicon for contacting optoelectronic (OE) chips on the carrier.
SiOB designs have only put the optoelectronic chip and a single passive optical component on the SiOB.
Referring to FIG. 1, a typical SiOB 10 is shown, where a laser diode (LD) 12 is be placed near the edge of a large socket 14 in the SiOB 10. The socket is there to align a lens (not shown) in front of LD 12, but it also permits the optical beam to emit from the SiOB 10 without hitting the SiOB surfaces.
After the laser diode 12 is placed on this SiOB 10, a large area photodetector (not shown) is brought up near the edge 16 of the SiOB in front of the LD 12 and a DC light output measurement is made. Then, a communication single-mode fiber is brought near the LD output, and a small portion of the light is collected for an AC measurement. This testing methodology requires access to the area directly in front of the LD and multiple alignments of test fixtures.
These SiOB designs are limited as to where optical devices can be placed or attached thereon since access is needed to these devices for testing.
During the assembly of this type of SiOB, the OE chip (LD, etc.) is usually the first component to be attached, and it must have AC and DC tests made prior to assembling all the other components on the SiOB. This testing must be accurate and done rapidly to keep manufacturing throughput high and manufacturing cost low.
Therefore, a need exists for testing optical devices, such as, lasers in-situ, which permits placement of such devices anywhere on a SiOB. A further need exists for a test probe which permits accurate and rapid testing of optical devices to keep manufacturing throughput high and manufacturing cost low.
An optical testing device includes an optical fiber having a first numerical aperture at a first end of the optical fiber. A positioning structure is attached to the optical fiber for moving the first end of the optical fiber to any portion of a substrate for testing an optical device. The optical device may be disposed at any location on the substrate and provides a light beam with an emission angle less than the first numerical aperture. A test head collects the light beam through the optical fiber to test the optical device. A method for positioning the optical fiber and testing the optical device is also disclosed.
These and other objects, features and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.